DESCRIPTION (Investigator's Abstract): This project is designed to study the influences which may produce differences in taste bud distribution. Fungiform papillae are studied from human cadaver tongues to compare the innervation, epithelium connective tissue and blood supply among specimens with high and low taste bud densities, respectively. Taste bud development is studied to see if the differences arise early in life. A method has been developed which permits taste pores in living humans and animals to be counted by videomicroscopy of the tongue surface. Each taste pore is the portion of a single taste bud which is in contact with the tongue surface. It is hypothesized that taste buds increase in number by division, and this hypothesis is tested by observing taste pores in rabbits over a period of time to document whether two pores arise from one. The genetic basis of taste bud distribution and taste perception is studied in inbred strains of mice. It appears that, among other differences, "genetic non-tasters" have fewer taste buds than "tasters". Since members of the same inbred strains of mice are genetically very similar to each other, the differences in their taste bud distributions are attributable to environmental influences. It is hypothesized that hormones influence the relative distribution of taste buds among individuals, and this hypothesis is tested in mice. They also test whether single nerve fibers that innervate fungiform papillae with a large number of taste buds yield larger taste responses than nerve fibers that innervate papillae with fewer taste buds. It is evident that some of the variation on both normal and abnormal taste perception is due to variation among subjects in taste bud density.